Development of an Intrinsically Safe Circuit Arc Simulation Platform and Characterization of Arc Discharge

In order to study the influence of mechanical vibration and current intensity on the characteristics of fault arc discharges in AC circuits under loose wire connections, in this paper an intrinsically-safe circuit fault arc experimental platform driven by a spark generator is constructed according to IEC standards. A large number of fault arc tests is conducted, revealing three types of discharge waveform characteristics in pure-resistance AC circuits, namely closed, open, and contact arc discharges. Upon analyzing the discharge energy measurements obtained through experiments, it has been determined that the risk associated with closed arc discharges is significantly greater than that of open and contact arc discharges. Based on this, three types of discharge waveforms in closed state are obtained, which were classified in to three types. Among them, type I discharges have the largest discharge energy and power, while type III arc discharges lasted the longest. The discharge energy of Class II arcs is the lowest, and their duration is nearly equivalent to that of open arcs.. The results show that in pure-resistance low-voltage AC circuits, when the normal current intensity of the circuit changes, the discharge time of type I closed arc will not be affected, and the discharge time will remain between 22 μs and 26 μs. The discharge energy and power of the arc increase as the normal operation current increases, and the power change is proportional to the current intensity. For type I closed fault arcs caused by electrode looseness, the discharge time, energy and power are not affected by the degree of looseness.